Abstract:

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Tea polyphenol loaded alginate-chitosan microspheres were prepared by ionic gelation method for controlling tea polyphenol release by using various combinations of chitosn and Ca2+ as cation and alginate as anion.Scanning electron microscopy were used to investigate the surface characteristics of tea polyphenol loaded microspheres. These microencapsulated beads were evaluated as a pH-sensitive system for delivery of tea polyphenol. The main advantage of this system is that all procedures used were performed in aqueous medium which may preserve the tea polyphenol bioactivity. At pH7.4, the amounts of tea polyphenol released increased significantly as compared to those released at pH1.2. It is evident that the rate of tea polyphenol release could be controlled by changing the chitosan and the calcium chloride concentrations.

Abstract: Stability and disintegration of natural polyelectrolyte complex microspheres for protein
drugs delivery have been extensively investigated because of their great influence on the drug
release patterns. In this study, we tested stability of microspheres with alginate (Alg) core layered
by either chitosan (Chi) or glycol chitosan (GChi) by examining release profiles of fluorophorelabeled
bovine serum albumin (BSA) and lysozyme (Lys) from the microspheres. While GChi shell
was disintegrated quickly, Chi-shell microspheres showed good stability in PBS. Disintegration of
the coated layer induced the core material instable. The results indicated that while the charges of
the shell material provided additional diffusion barrier against the protein release, the key factor to
hold the proteins inside the microspheres was the integrity of the outer coating layer.

Abstract: Microencapsulation technology is widely used in many industries recently because the stability of core material can be improved and the release characteristics can be modified. In this investigation, cinnamon oil was microencapsulated by simple coacervation. The size distribution is narrow and the mean diameter is 53.79 μm. The surface morphology of the resultant microcapsules was also characterized scanning electron microscopy (SEM). The results showed that the rates of cinnamon oil released from microencapsulation were not only affected by relative humidity in the microenvironment around microencapsulated powder, but also affected by the temperature.

Abstract: Sulforaphane (SF) has been proved to be an effective anticancer agent according to its experiments both in vitro and in vivo. To date, there is few reported method to deliver SF for increasing its bioactivity and stability. In this study, a novel pH-sensitive microsphere composed of water-soluble carboxymethylated chitosan (CMCS) and alginate mixed with sodium sulfate was developed for SF delivery. Swelling studies and release characteristics under different pH values of microspheres were investigated. Then, the release of SF from test microspheres was studied in simulated gastric and segmented intestinal media. It has been found that the SF cumulated release in 5h was increased from 55.89% to 76.73% when the microspheres mixed with sodium sulfate. In addition, the stability of SF embedded in CMCS/alginate microspheres was also significantly improved. Under pH 7.4, free SF had a severe degradation of approximate 100% within 210 min, whereas the change of the SF in microspheres was only a decrease of about 10%. The results suggested that the microspheres of CMCS and alginate could be a suitable pH-sensitive carrier to increase the stability of SF in the segmented intestine.

Abstract: Temperature-sensitive calcium alginate-based microspheres were prepared in two steps. Firstly, free-radical polymerization of temperature-sensitive N-vinylcaprolactam monomer was performed in aqueous solution of sodium alginate, yielding a mixed aqueous solution bearing temperature-sensitivity composed of poly(N-vinylcaprolactam), sodium alginate-graft- poly(N-vinylcaprolactam) and sodium alginate. Then temperature-sensitive composite microspheres were prepared by inverse emulsification-crosslinking using the as-prepared solution as water phase, n-hexane as oil phase, Span-85 and Tween-85 as emulsifiers and calcium chloride as crosslinker respectively. The morphology and temperature-sensitivity of the composite microspheres were investigated by scanning electron microscope and turbidity method respectively. The controlled release behavior of the microspheres towards temperature was investigated preliminarily using berberine as a model drug.

Abstract: Multi-membrane hydrogels are newly promising carriers in biomedical fields for their gentle gel condition and excellent biocompatibilities. In this study we focused on the dual control release property of alginate-based onion-like multi-membrane hydrogels hybrid with polylactic acid microspheres. The results indicated that the PLA microspheres evenly distributed in each of the hydrogel membranes. And the drug delivery in physiological saline is well controlled which can be promising in transport drugs, genes, protein, etc.